Seal



Nov. 10, 1953 D. MURPHY SEAL 2 Sheets-Sheet 1 Filed Sept. 24. 1949 D.MURPHY Nov. l0, 1953 SEAL 2 Sheets-Sheet 2 Filed Sept. 24. 1949 NYWNPatented Nov. 10, 1953 UNITED STATES PATENT OFFICE SEAL Daniel Murphy,New Castle Pa.

Application September 24, 1949, Serial No. 117,613

`2 Claims. 1

My invention relates to seals for rotary shafts, and particularly toseals for the shafts of rotary pumps.

In United States Letters Patent No. 2,251,020, granted to me August 8,1944, I disclose a pump which has enjoyed success in pumping slip in thepottery industry, and in United States Letters Patent No. 2,453,249,granted to me November 9, 1948, and in United States Letters Patent No.2,505,868, granted to me May 2, 1950, I illustrate and describe certainnew and useful improvements in seals for the rotating shaft of such apump.

My present invention consists in further improvements in such seals orsealing devices, whereby the devices become effective not only to makethe rotating shaft secure against the escape of the fluid being pumped,but also to withstand and retain lubricant injected in the shaftbearings under the high pressure of a lubricant gun or pump.

The invention will be understood upon reference to the accompanyingdrawings, in which:

Fig. 1 is a view, partly in side elevation and partly in verticalsection, of a pump in which a sealing device of the invention isorganized;

Fig. 2 is a fragmentary view, showing partly in side elevation andpartly in vertical section, the structure of such sealing device and theadjacent parts of the pump to larger scale;

Fig. 3 is an "exploded view, showing the several elements of the sealingdevice in proper relative positions Afor assembly; and

Fig. 4 is a view in front elevation of one of the seal members.

The pump shown in the drawings comprises a body I, within which isformed the usual impeller chamber 2, and within the chamber a vanedimpeller 3 is borne upon a rotary shaft 4. Under the iniiuence of therotating impeller, liquid is drawn from an intake passage 5 through theeye B of the pump, and is delivered at the periphery of chamber 2 to adischarge passage 1. When the pump is in operation, the pressure eX-erted upon the rotating impeller, holds the impeller in abutment uponthe side wall on the right (as seen in Fig. 1) of the pump chamber 2.This side wall is advantageously formed as a removable and replaceableplate 8.

The body I of the pump carries rigidly mounted upon it a windowedhousing 9; and within the housing two bearings are formed, whichrotatably support the shaft 4 of the impeller. The shaft 4 at its outerend (to the right, Fig. 1) is adapted to be coupled to, or otherwisebrought into powertransmitting connection with, a suitable motor; andthe mounting of the shaft in said two spacedapart bearings is elfectiveto prevent whipping of the shaft when the pump is in operation.

One of the bearings includes an annular block I0, conveniently made inone piece with the housing 9; and the block I0, together with theintegral housing, is secured by set-screws II in a cylindrical seat I2,formed exteriorly upon the body I of the pump. The other bearingconsists of concentric rings I3 and I4 with rolling members, here shownto be balls I5, arranged in the race formed for them by and between therings. The inner ring I3 ts snugly upon the shaft 4; the outer ring I4ts snugly within, and is adapted to slide longitudinally within a boreI6 formed in the housing 9. The bearing I3, I4, I5 abuts laterally upona ring I l, which, by means of a set-screw I8, is secured to the shaft4. The assembly of bearing and ring is held between two nuts I9 and 29,that, encircling the shaft 4 and movable freely along shaft 4, makescrewthreaded engagement with the bore I6. The windows in the housing 9afford access to` the inner nut I9, for adjusting it.

Means are provided for lubricating the two bearings, consisting of alubricant cup 2I and a lubricating tting 22, with ducts leading to thebearing surfaces.

It will be seen that in the second bearing (the bearing to the right),and particularly in the ring I'I and the cooperating nuts I9 and 29means are found for adjusting the shaft 4 longitudinally, to compensatefor the wear of the impeller 3 upon the plate 8.

It is requisite that provision be made against a withdrawal of lubricantfrom the bearings by the suction of the operating pump, and against in.-gress to the bearings of the liquid that is pumped, a supply of whichremains standing in passageway 5 when the pump is at rest. In the meansto such end, the improvements of my present invention are found.

In the seating of the bearing block III in the body I of the pump anannular shaft-encircling plate 23 is, by the screws II, clamped to placeat the left-hand end (Fig. 1) of the cylindrical seat I2, forming ineffect an integral part of the stationary pump body, as well as aneffective part of the seal structure, presently to be described. Thisannular plate is provided with a rigid shaftencompassing sleeve orcylindrical extension 24. The extension is in this case integral withthe plate. The plate 23 with its sleeve-like extension 24, when clampedto place. constitutes within block l the bearing member proper. Theextension 24 carries interiorly a bronze bushing 40, within which theshaft turns. Lubricant ducts are indicated at 4I, 42. The annular plate23 is clamped with sealing eiect to the wall of the pump casing, and itsintegral sleeve-like extension is the immediate bearing member for theshaft.

In the assembly the plate 23, with its bronzebushed extension 24, snuglyencircles the shaft. The fit is, however, not so snug as to exert anyrestraint upon the free turning of the shaft within the sleeve. Acylindrical space 30, formed by and between the shaft 4 and the blockI0, is closed to the left by the plate 23 with its extension 24, and tothe right is closed by a block 32 having a sleeve-'like extension 33that isadjustably anchored in the bearing block Ill by setscrews 34.This chamber 3U is normally filled with a supply of lubricating greasedelivered under high pressure through .passage 3l. The block 32 mayinclude within its outer end a channel in which a felt vpacking 63 iscontained, and between the block and the body I0 of the bearing a rubbergasket 64 is clamped, thus preventing the escape of grease outward fromchamber 36.

A sealing structure cooperates with the shaftencompassing member 23 toprevent liquid from being sucked into the pump from the bearingstructure when Ythe pump is in operation, and alternately to preventliquid from draining from the pump into the bearing structure when thepump is at rest. The sealing structure comprises essentially two sealmembers or devices` A and B, one rotatable with the shaft 4 and theother secured against rotation, with the two arranged in yieldingabutment upon one another on sealing surfaces extending annularly of theshaft 4. The first seal member or device A comprises a collar portion-26 keyed, as at 21, to the shaft 4. The collar portion 26 is thus madetorotate with the shaft, while being adapted to slide on the shaft tomaintain,` as presently will appear, snug contact with a collar portion25 of the second seal member or device B.

Organized with the collar portion 26 is a tubular member of sleeve 284formed of a flexible and elastic material that is resistant vtodeterioration under the effects of both the liquid being pumped and thelubricant used in the vbearing structure. A synthetic rubber known onthe market as Neoprene has been found to be a suitable material of whichto form the member 28, but it will be understood that the invention isnot predicated upon the selection of the particular material which maybe used. `Im portant characteristics of `the member 28 are that'it ismounted in shaft-encircling position; that at one end of its tubular orring-like body it is wedged, as at 28a, against the chamfered edge of arigid sleeve E50 on the shaft, and by means of a keeper ring 29 issecured in sealed union to the body of the shaft. The body of member 23includes a iinage 28h that fits a groove 26e formed in the collarportion 2'6, Where it is secured in liquid-tight union vby means of akeeper 26h which engages a flange '28Cl on member 28 and isdrift-'fitted to the body of collar 26. The assembled `seal member ordevice A is adapted to rotate in unison lwith the'shaft 4, and thecollar portion 26 is free to move axially of the shaft against, andassisted by, or the force of a spring 16 arranged as shown. Preferably,if not essentially, the elastic body of the member 28 is axiallycompressed inthe assembly whereby member 28 cooperates with the spring16 to press and maintain the collar portion 26 in snug running contactwith the fact of the wearing or collar member 25. A sealed engagement ofthe relatively rotatable portions 25 and 26 is maintained both when thepump is in operation and when it is idle. The member 28, by virtue ofits elastic nature and organization in the assembly, is adapted axiallyto expand and retract to maintain such sealed Vengagement even though aslight misalignment exists between the relatively rotatable parts.

The collar portion 26 of the seal member or device A is herein shown tobe formed of a steel portion 26a and an annular brass portion 26hhavlubricating graphite inserts 26d.

The proportions and dimensions 0f the several elements of the sealingdevice are such that, when the elements are assembled on the shaft, thescrewing of the body of the impeller into place on the threaded end ofthe shaft will compress the spring 16. The seal assembly A isliquidetight and capable of withstanding thehigh pressure of lubricantwhich is injected through the fitting 22 into the shaft bearings, andwhich works its way along the shaft to the chamber that houses thespring 'i6 within the flexible sleeve member 28.

A slight clearance is provided between the collar member 26 and theshaft 4, Yso that the collar may wobble inthe eventthat there is anymisalignment of the rotating parts, and by such wobbling to maintaintight surface-to-sur'face contact with the wearing member 25. However,if there is substantial wear of the bearings, or if the bearings asoriginally provided have a running tolerance substantially more than onethousandth of an inch, the lateral play of the shaft may in time resultin unequal wear ibetween the collar members or portions 26 and 25, withthe result that leakage will develop. It is in contravention of thisundesirable consequence that the collar portion 25 of the seal member ordevice B is formed separately from the bearing portion 23 and itscomplementary part 80. "The portion 25 is adapted to wobblesympathetically with the collar member 26 and thereby maintains thedesired uuid-tight engagement in spite of any misalignment of therotating parts.

As vshown in the drawings, the member 25 comprises a two-piecestructure.; that is, a brass ring 25a within which is secured a ring25hof such bearing material as cast iron. The ring 25h at its left-handend extends vfrom the ringv portion 25a and provides theshaft-encircling faceagainst which the collar member 26 bears, while atits right-hand end the ring 25h is continued in a bearing sleeve portion25h. The bushing 4i) is extended to the left of the stationary bearingportion 23 to receive the seal member 25 in Aa loose fit, and a key 5lon sleeve Vportion 25h engages a slot 5| a in bushing 40 and secures themember '25 against rotation, while permitting to required Adegreetheaxial and angular movements of such member relatively to the stationarybearing portion. The member Y25 is sealed to the stationary bearingportion by means of a flexible shaft-encompassing sleeve A52 formed inthis case of the same material as the sealing element 28.

The body of `the sleeve. is frusto-conical .in form, having at itslarger end a lip or edge 52a that is 'received in a groove 86a formed inthe insert or auxiliary portion vof the stationary bearing or plateportion '23. The smaller end of the frusto-conical sleeve is forme/cl tofit snugly upon theextension 25h of seal-member 25, and is clampedthereon by` means of a collar 90 having a tapered bore 90a (Fig. 3) thatengages the conical surface of the sleeve 52. Thesleeve has a flange 52hthat is sprung through the bore of collar 90, as shown in Fig. 2. Thecollar 90 is recessed as shown at 90b, whereby when the seal parts areassembled and compressed axially on the shaft part of the frusto-conicalbody of the sleeve 52 is buckled or turned back, or reversely curved,`and caused to form a bulge that snugly fits the annular recess 90b,while the remainder of such frusto-conical body is pressed tocylindrical form and externally reinforced and supported by a`cylindrical annular extension or portion 80h on the stationary insert80 of the ybearing member 23. The frusto-conical flexible sleeve, sealedto and extending between seal mem-V ber 25 and stationary body portion80, is enclosed between and within the portions `9i) and 80h, and suchportions provide a complete metal encasement of the flexible sleeve 52,with the exception of a narrow, open, circumferential clearance Gbetween the portions. The encased flexible sleeve is very effective towithstand the high pressures of lubricant delivered to the bearingstructure and filling the reservoir within the flexible sleeve. A spring`11 in such reservoir simply serves to oppose the spring 16 of the firstsealing device described, and to keep the annular sealing surfaces ofthe members 25 and 26 in the desired yielding contact.

Provision is made to assist the graphite inserts 26din lubricating the,contacting faces of the members `25 and 26. Advantageously, the bore ofthe member 25` is enlarged for a part of its extent as indicated at 25din Fig. 4, to provide when assembly has .been made, Fig. 2, a chamber 62for a supply of lubricating grease. Within the body of the inner ring25h of the member, a plurality of pockets 25e isformed, the pocketsextending radially from the enlargedbore portion 25d and being locatedat points spaced apart circumferentially of the member 25. And from eachof said bores 25e a small passage 25j leads to the face of the wearingmember that makes `contact with the collar 26. The pockets 25e are inthis case 1/8 inch in diameterthe passages 11g inch, and the mouth ofeach passage is countersunk to eliminate sharp edges on the face thatreceives the face of 'the rotating collar member 26.

When making assembly of the sealing device, the chamber 62 and the boresand passages 25e and 25j are packed with lubricating grease, and whenthe pump is in operation this grease works its way to the meeting facesof the relatively rotating members 25 and 26 and lubricates them.

The lubricant supplied through the passages 3l and 4I may be forced,under the high pressure of a grease pump connected to the fitting 22,between the shaft 4 and the bushing 40 and into the chamber 62,. toreplenish the supply of lubricant as needed. In fact, not only is thechamber 62 thus charged, but the `reinforced spaces within the sealingmembers 28 and 52 may be also filled, to serve as reservoirs oflubricant.

The bores and passages 25e and 25j have a second utility.` They functionto augment the dissipation of the heat generated by the friction betweenthe faces of the rotating collar member 26 and the non-rotating member25. But for the heat dissipation thus obtained, the effective life ofthe seal would be impaired; that is, no matter how eiiicient thelubrication is, substantial heat tends to develop and endanger the 6,life of the rubber sealing members 28' and 52. The augmented dissipationof heat provided by the feature described eliminates this danger.

It will be perceived that I have sealed the passage of the pump shaftthrough the wall of the pump against leakage, by means of a simpleorganization, and that I have provided a bearing for the pump shaft thatis easily assembled and separated. As in course of operation the wearingplate 8 and the impeller 3 are worn away, they may readily be removedand replaced, and that as operation continues the adjustment nuts I9 and20 constitute means for compensating for the wear.

It is to be remarked of the seal structure described that the wearingmember '25 is mounted independently of the shaft 4 on the stationary`extension of the bushing or sleeve 40 that carries the shaft loadwithin the bearing member 23, and, while being secured by key 5| againstrotation, the member 25 is assembled with a loose t, whereby it is freeto float and to wobble in all directions, in order to obtainself-alignment with the associated rotating parts. The bushing 40extends from the bearing member 23 a sucient distance to provide amplesupport for the floating member 25, and it will be noted that theflexible externally reinforced member 52 allows the member 25 to moveaway from the member 23 to maintain contact with collar 26 withoutbreaking the seal. At the same time the flexible member 28 with equalpressure urges the floating collar 26 into self-aligning contact withmember 25. Thus, the rotating members 29, 28 and 26, and thenon-rotating members 25 and 52 comprise a floating seal that isyieldingly held in assembly between the stationary member 23 and thesleeve 5U that rotates with the shaft 4. The engagement of the collar28h of member '28 in groove 26e seals the member 28 to the collar 26,and maximum flexibility and self-aligning activity of the parts may beobtained, it being manifest that the keyed union 2'! of the collar 26 tothe shaft relieves the member 23 from torque, just as the keyed union ofmember 25 to bushing 40 safeguards the elastic member 52 from torque.`These features of the sealing device are of particular value in rotarypumps in which end play usually develops in the impeller shaft, and thebearings sooner or later wear out of true with the shaft. It will beunderstood that if both sealing members 25 and 26' were mountedimmediately on the shaft 4, with one member held against rotation andthe other rotating with the shaft, the desired effect would not beobtained, for if the bearing ran out of true by as much as threethousandths of an inch the two contacting seal members 25 and 26 :inrelative rotation would chatter or repeatedly hit at two points spacedapart with respect to the axis of the shaft, and thus would form anopening between such members that would destroy `the seal and causeleakage. This I have discovered by experience, and the objection iseliminated in the structure ofV my present invention.

.Another important feature of the invention is to be noted, I havediscovered that, while the individual floating or wobbler mounting ofthe rotating and non-rotating seal members 26 and 25, respectively,tends to maintain the bearing` to produce a wiping action between thesnugly .contacting and'relativelyrotating: faces of the two members-fa.rubbing action that is: elfetye, backv and forth, on lines thatV extendradially` f Vthe axis` of the shaft 4., an action that is; caused by onemember (2.5.' or 2,6) being eccentric relatively to the other even.though their` meeting faces'. may; be maintained in snugsurfacertosurface contact. This rubbing; action tends to produce acondition that sucks the lubricant out of the reservoir 62, causing theengaged and relatively rotating faces. of the. members 5:v and 216 torun dry, With the. effect that the` fluid-tight seal` is. impaired, and'particles. of abrasive are admitted from the pump chamber or passa-geinto. the. seal structure, thereby destroying its effectiveness.

In overcoming thisA objection, I provide an annular shoulder thatextends from the bearing face of one of the seal members (25, 26) into.a recess in the other seal member. In this case the ring- 26 isprovided. with a shoulder 26e that extends from the annular bearingVface of the ring, and in the assembly (Fig. 2) extends into the boreportion 25d ofthe ring 25, but suchextension of the portion 253e intothe bore portion 25d does not so completely fill such bore portion as toimpair the bore portions function as a reservoir for lubricant. The iitof the shoulder formed by the extending body of ring portion 25e in thebore of ring 25v does not inhibit the wobbling of the two rings in themanner required to maintain a snug running contact between the engagedbearing faces of the two rings, but the nt is effective to prevent therelative oscillating or side shimmying of the two seal members 25 and2B.

After a prolonged and adequate period of service, it may develop, as inany p-iece of machinery whose parts are subject to Wear, that the sealmembers will require renewal. In my structure this may be accomplishedwithout tearing down the pump. It is necessary only to disconnect thecoupling ofthe shaft 4 to its driving motor, and then remove the housing9- fromthe shaft and the pump body l. Access to the sealing device isvthereby afforded. And in case a leak should develop in the sealingdevice at a time when it is inconvenient to make immediate repair, theblock 32 may be removed, and packing placed in the chamber 30. Then theblock may be reassembled and tightened against the packing. In thisfashion the pump maybe operated until Such vtime as the sealing devicecan be renewed.

The sealing device described will prove usefull in many apparatus, otherthan pumps, in which it isy desirable to seal a rotating shaft againstthe escape of fluidwhile providing for high pres-- sure lubrication ofthe bearings and relatively-A rotating parts, and Within the scope ofthe appended claims such varied utility of the; sealingA device, as Wellas many variations and modifica-- tions in the structure of the device,are held in contemplation.

I' claim:

l. A seal for a rotaryl shaft extending through a stationary body, said'seal comprising two shaftencompassing devices, one rotatable withv theshaft and the other secured againstrotation, and' arranged yieldingly toabut upon one. another on` sealing surfaces that extend annularly about:the shaft, said device which issecured against rotation comprising ashaft-encompassing member having a rigid bushing portion engaging said;shaft, a second shaft-encompassing; member having a sleeve extensiontelescopedy in a loose, fit

upon' saidbushingportion and keyed, thereto. to

permitrelative Wobbling movement of said members, with their telescopedportions axially of said shaft, a flexible shaft-encompassing sleeve.extending between, and secured at its opposite ends to said members, aVcollar portion clamping one end of said flexible sleeve to. the sleeveextension of said second member,v and a cylindrical extension, on thefirst-mentioned memberradially spaced from, and concentric with thebushing portion thereof, said. collar portion and said cylindricalVextension-formingbetween said members an enclosure that embraces' andexternally' supports the Wall' of said 'exiblesleeve in substantiallyitsf entire extent between said shaftencompassing members, whereby anenclosed and reinforced chamber is provided to receive highpressurelubrication, said collar portion including an annular recess concentricwith said shaft, thel wallV of said exible sleeve in its extent betweensaid members including a reversely curved portion that is snugly engagedand supported in saidrecess.

2. A seal for aV rotary shaft extending through a, stationary-body, saidseal comprising two shaftencompassing devices,v one rotatable with theshaft and the other secured against rotation, and arranged yieldingly toabutupon one another on sealing surfaces that extend annularly about thesha-ft, said device which isl secured against rotation comprising ashaft-encompassing member having a rigid bushing' portion engaging saidshaft, a second shaft-encompassing member having a sleeve extensiontelescoped in a loose t upon said bushing portion and keyed thereto. topermit rela-tive wobblingvmovement ofsaidv members with theirvtelescoped portions axially ofsaid' shaft, a flexible shaft-encompassingsleeve of truste-conical form. extending between` and secured at itsopposite ends to, said; members, a collary portion clamping one end offsaid flexible sleeve to the-sleeve extension ofv said second member,andl a cylindrical extension on the firstmentioned member radiallyspaced from and concentric with the-bushingportion thereof, saidv collarportion and said cylindrical extension forming between said members anenclosure that embracesand externally supports the wall of said`flexible sleeve in substantially its entire extent'between saidshaft-encompassing members, whereby: anv enclosed` and reinforcedchamber is'v provided to receive high-pressure lubrication, said collarportion including a conical bore that externally engages said' flexiblesleeve fora part of its extent axially of said shaft, said collarportion alsoA including radiallyV outward from said conical bore anannular recess, and the wall. of, Said flexible sleeve in. its extentlfrom said conical; bore; being reversely curved in a portion that 1S:snugly engagedv andr supported in said recess,

Y DANIEL. MURPHY;

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,226,001 La Bour Dec. 24, 1940 2,250,348; Beier July 22, 19412,365,351 Matter Dec; 1'9, 1944 2,399,164 Schilling May 7, 194562,444,713 Solari July 6, 1948 2,479,178Y Murphy Aug. lr6, 1949.2,505,868-` Murphy May 2, 1950-Y

